Crankcase breathers

Post any technical questions or queries here.
Post Reply
User avatar
Robbie224
850 Super
Posts: 147
Joined: Sat Apr 30, 2022 1:23 am
Location: Portsmouth
Been thanked: 6 times

Crankcase breathers

Post by Robbie224 »

1275gt has 3 breathers one on clutch end, one off rocker cover and a third fan end. Question is are they all better with black water type pipes on then vented down towards ground or each one have its own filter better?
Thanks
User avatar
BAD942B
998 Cooper
Posts: 363
Joined: Wed Apr 05, 2023 6:34 pm
Location: Stratford upon Avon
Has thanked: 3 times
Been thanked: 1 time

Re: Crankcase breathers

Post by BAD942B »

if they are vented down to the ground they can blow out oil & contaminants, not great for bikers or cyclists if its wet, breathers dont just blow, they suck contaminants in when the engine cools.
Use small filters on the pipe ends
Chris A
User avatar
Robbie224
850 Super
Posts: 147
Joined: Sat Apr 30, 2022 1:23 am
Location: Portsmouth
Been thanked: 6 times

Re: Crankcase breathers

Post by Robbie224 »

Perfect thank you
User avatar
Spider
1275 Cooper S
Posts: 4849
Joined: Mon May 07, 2012 6:10 am
Location: Big Red, Australia
Has thanked: 181 times
Been thanked: 64 times

Re: Crankcase breathers

Post by Spider »

I don't think the one on the rocker cover is original as none of the UK types I've even seen had an Oil Separator on them. Usually, a vented Oil Filler Cap is fitted to allow for a metered (Clean) Air Entry point.

The Crankcase breather set up was one thing the factory got very right in my view. For any road car, I'd suggest plumbing it up as they had it. It will remove the smell and more importantly, remove moisture from the Oil.
User avatar
Peter Laidler
1275 Cooper S
Posts: 6389
Joined: Sat Jul 15, 2017 5:35 pm
Location: Abingdon Oxfordshire
Has thanked: 135 times
Been thanked: 113 times

Re: Crankcase breathers

Post by Peter Laidler »

I'm a big believer in that view about the factory breathers Chris and Robbie. Working from that known datum, you can soon start to tell what you are adding is working good and what ain't. Good advice
Post Reply